Flashing pebble dash stucco.
I want to add a sun porch on the side of an old house with pebble dash stucco. The top of the shed roof will be against the stucco wall. Do I remove enough of the existing stucco in order to flash and then re-stucco over it, or do I install over the stucco and use a sealant to fill all the gaps?
The flashing must always, always, always go under the stucco and not over the stucco.
As you can see, the dash stucco surface is highly irregular so it is more important to flash under the stucco.
I have said this many times, flashing needs to go under the stucco and not over the stucco. A lot of our work these days is fixing leaks over roofs and windows. The stucco needs to be cut off above the roof line, flashing put on the substrate, whether it is plywood, osb, brick, whatever. Then the stucco patched back.
Putting flashing over the old stucco ( or new stucco )doesn't work. Stucco is a porous material and water will penetrate the stucco, even if it has been painted. I see flashing put on over the stucco a lot, and it gives me a sharp pain in the stomach to see this. Also, this flashing over the stucco almost always has a ugly gob of caulking or black stuff around the edge, and gobs of caulk on the nail heads. I hate to be redundant, but I figure I must keep informing the world of the error of it's ways until this practice stops.
This simple S flashing works great for flashing over metal roof flanges, or over flashing that was put over the stucco. Sometimes it's not practical to tear off the old flashing, so an S flashing is like putting a roof over the flashing.
The stucco is cut off above the roof flange and "S" flashing, also known as "Z" flashing, is nailed to the sheathing. On this 120 year old house, the sheathing is one by eights.
Another roof, the same way. The top flange of the S flashing is sealed up the stucco with peel and stick rubber flashing tape. The gap is the patched with lath and stucco.